and many more benefits!

Find us on Facebook

GMAT Club Timer Informer

Hi GMATClubber!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Show Tags

24 Jul 2012, 19:50

Is \(|x - y| \gt |x + y|\) ?

\(x^2 - y^2 = 9\) \(x - y = 2\)

Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient EACH statement ALONE is sufficient Statements (1) and (2) TOGETHER are NOT sufficient

Statement (1) by itself is insufficient. S1 gives us information about \((x - y)(x + y)\) but does not tell how \((x - y)\) and \((x + y)\) compare to each other.

Show Tags

Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient EACH statement ALONE is sufficient Statements (1) and (2) TOGETHER are NOT sufficient

Statement (1) by itself is insufficient. S1 gives us information about \((x - y)(x + y)\) but does not tell how \((x - y)\) and \((x + y)\) compare to each other.

Show Tags

in general if you want to plug in numbers in questions like these, you need to consider positive, negative and fractional values of all the variables to eleminate/consider one optionCheers
_________________

Show Tags

25 Jul 2012, 01:10

teal wrote:

Is \(|x - y| \gt |x + y|\) ?

\(x^2 - y^2 = 9\) \(x - y = 2\)

Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient EACH statement ALONE is sufficient Statements (1) and (2) TOGETHER are NOT sufficient

Statement (1) by itself is insufficient. S1 gives us information about \((x - y)(x + y)\) but does not tell how \((x - y)\) and \((x + y)\) compare to each other.

I can't get the right numbers to test statement 2 to prove it Insuff. Please help. All the numbers I tried have me NO. Please help.

In fact, the given inequality can be rewritten as \((x-y)^2>(x+y)^2\) - we can square both sides, as they are both positive. Rearranging the terms, the question becomes \(xy<0\) (is the product xy negative)?

Then, it is much easier to understand that neither (1), nor (2) alone is sufficient.Taking both statements, one can explicitly find the values of x and y (although not necessary), and check whether their product is negative.That's why the correct answer should be C.
_________________